The purpose of investigating the phosphorylation of ribosomal and ribosomal-associated proteins on a molecular level is to determine the effects of these modifications on the control of translation. Since cAMP has been shown to mediate the regulation of a number of basic metabolic systems by phosphorylation, we wish to investigate ribosomal phosphorylation as a possible means of controlling protein synthesis. As a preliminary step in this investigation, the individual cAMP- dependent and cAMP-independent protein kinases have been characterized, and the 70 ribosomal proteins from rabbit reticulocytes have been identified. Phosphorylated ribosomal proteins will be distinguished by three-dimensional electrophoresis, and other components involved in protein synthesis will be analyzed for phosphate acceptor activity. The aim of this study is a functional analysis of the phosphorylated components and an examination of the effects of modification by phosphorylation on the various partial reactions of protein synthesis. These studies will be correlated with phosphorylation patterns of ribosomal proteins in whole cells under a variety of conditions. Since the loss of cellular regulation is associated with a number of diseases including neoplasia, we propose a series of experiments designed to aid in the understanding of cellular regulation by analysis directed toward translational control.